List of top Chemistry Questions

Define Double Salt with one example.

What is meant by chelate effect? Give an example.

\[ \text{The conductivity of }0.001M\text{ solution of acetic acid is }3.905\times10^{-5}\;S\,cm^{-1}.\text{ Calculate its molar conductivity and degree of dissociation }(\alpha). \]
\[ \lambda^\circ_{CH_3COO^-}=40.9\;S\,cm^2mol^{-1} \]
\[ \lambda^\circ_{H^+}=349.6\;S\,cm^2mol^{-1} \]

Draw the structure of the semicarbazone of acetone.

\[ \text{A black-brown coloured solid }(A)\text{ when fused with }KOH\text{ in the presence of air, produces a dark green compound }(B)\text{ which on electrolytic oxidation in alkaline medium gives a dark purple coloured compound }(C).\text{ Identify }(A),(B)\text{ and }(C).\text{ Write the reactions involved.} \]

Name two coordination compounds which are important in biological systems.

Define Ambidentate Ligand with one example.

The rate of the chemical reaction doubles when the temperature is raised from \(298\,K\) to \(308\,K\). Calculate activation energy \((E_a)\) for this reaction assuming that it does not change with temperature. (Given : \(R = 8.314\,J\,mol^{-1}\,K^{-1}\), \(\log 2 = 0.30\))

Calculate emf of the following cell at \(298\,K\) : \[ Cr(s)\,|\,Cr^{3+}(aq,\;0.1\,M)\,||\,Fe^{2+}(aq,\;0.01\,M)\,|\,Fe(s) \] (Given : \[ E^\circ_{Cr^{3+}/Cr}=-0.74\,V, \] \[ E^\circ_{Fe^{2+}/Fe}=-0.44\,V, \] \[ \log 10 = 1 \] )

Assertion (A) : p-nitrophenol is more acidic than phenol. Reason (R) : Nitro group is an electron-withdrawing group, it stabilises phenoxide ion by dispersal of negative charge.

Assertion (A) : All aliphatic aldehydes give a positive Fehling’s test. Reason (R) : Aliphatic aldehydes are reduced by Fehling’s reagent.

Assertion (A) : Highest oxidation state of Mn is +7 in first series of transition elements. Reason (R) : Transition metals exhibit variable oxidation states.

Assertion (A) : D (+) – Glucose is dextrorotatory in nature. Reason (R) : (+) represents dextrorotatory nature and D represents the configuration.

Primary, secondary and tertiary alcohols can be distinguished by :

Consider the following compounds : \[ C_2H_5NH_2,\quad (C_2H_5)_2NH,\quad C_6H_5CH_2NH_2,\quad NH_3,\quad C_6H_5NH_2 \] The correct increasing order of the above compounds on the basis of their basic strength is :

Identify the polysaccharide among the following :

The polypeptide chain in a protein has amino acids linked with each other in a specific sequence. This specific sequence of amino acids is called :

Which of the following ligands forms a chelate complex ?

The correct formula of Hinsberg’s reagent is :

Actinoids show larger number of oxidation states :

The major product of carbylamine reaction is :

Half-life (\(t_{1/2}\)) of a first order reaction is 1386 s. The value of rate constant is :

Consider the following reaction and identify A and B : \[ CH_3Cl + NaI \xrightarrow[\text{dry acetone}]{} A + B \]

Which of the reactions is used in the conversion of a ketone into hydrocarbon ?

Which of the following reagents are used to prepare primary amines by Hoffmann bromamide degradation reaction ? \[ (i)\quad \begin{array}{c} O\\ || \end{array} R-C-NH_2 \] \[ (ii)\quad NaOH \] \[ (iii)\quad Br_2 \] \[ (iv)\quad CHCl_3 \]